Oxygen sensors made of alkaline-earth-doped lanthanum ferrites
AssigneeRoth-Technik GmbH & Co. Forschung Fur Automobil-Und Umwelttechnik
InventorsKarl-Heinz Hardtl, Ulrich Schonauer, Andreas Krug
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Abstract
An oxygen sensor made of alkaline-earth-doped perovskitic lanthanum ferrites with the general formula: La.sub.1-x Me.sub.x FeO.sub.3-.delta. where Me is one of the alkaline earth metals, Mg, Ca, Sr, and Ba and x is the degree of doping, and the oxygen deficit of anion .delta.=0 to 0.25. The degree of doping of the lanthanum ferrites is x=0.1 to 0.3 and resistance is measured in the lanthanum ferrites as a function of oxygen partial pressure.
Claims1
Method for producing an oxygen sensor measuring resistance as a function of oxygen partial pressure, made of alkaline-earth-doped perovskitic lanthanum ferrites with the general formula
- La.sub.1-x Me.sub.x FeO.sub.3-.delta.
- where Me is one of the alkaline earth metals, Mg, Ca, Sr, and Ba, x is the degree of doping, the oxygen deficit of anion .delta.=0 to 0.25, and the degree of doping of the lanthanum ferrites is x=0.1 to 0.3 and is selected to provide a temperature independent resistance property to the oxygen sensor in a lean range comprising the steps of applying said alkaline-earth-doped perovskitic lanthanum ferrites, using thick film technology to a carrier and stoving or tempering;
- or stoving and tempering said alkaline-earth-doped perovskitic lanthanum ferrites applied to said carrier material, wherein said carrier is a non-metal oxide substrate, and said stoving step comprises drying said thick film on said substrate holding for 15 minutes at 120.degree. C., increasing a stoving temperature at 20K/min to 350.degree. C. and holding for 10 minutes at 350.degree. C.;
- increasing said stoving temperature at 20K/min to 1200.degree. C. and holding for 25 minutes at 1200.degree. C., and cooling at 20K/min to ambient temperature.
Dependencies are inferred from the claim text.